Security is an expanding field in which requirements for authentication of the identity of individuals is becoming increasingly important in many different situations. Identity authentication encompasses many different levels from simple ticket requirements for access to a charged entry environment to security requirements for access to restricted confidential areas.
Access to many different resources is required to be controlled. The resources may take many different forms including, but not restricted to the following. Physical resources such as locations (e.g. hotel rooms, secure areas, etc.), physical objects (e.g. safes, computers, etc.), and data resources (e.g. secure web sites, financial data, etc.).
Existing security arrangements include physical objects such as keys, Smartcards, etc. which can be passed between single individuals. Physical objects have the disadvantage that they can be mislaid or stolen. Secure physical mechanisms such as keys and locks (particularly using Smartcards) have a high cost of installation and upkeep.
There are also security arrangements in which a pass-code is memorised and used by an individual. Again, it is possible to pass this form of security means between individuals and, furthermore, it can be passed to more than one individual at a time. Pass-codes can be inadvertently disclosed to an untrustworthy party. Also, if specific credentials such as pass-codes remain fixed for long periods of time, there is an increasing risk of exposure.
Another form of security for individuals is referred to as biometrics, which is the biological identification of a person which includes the characteristics of structure or action. For example, iris or retinal patterns, hand geometry, fingerprints, voice responses to challenges, the dynamics of hand-written signatures, etc. are all forms of biometrics. Biometrics is a strong form of identity authentication of an individual; however, many forms have a high failure rate. Also, biometric identifications have the disadvantage that they are impossible to withdraw.